In recent years, an operation of an NC machine tool has become complicated because of its multi-axis and multi-system configuration, and an NC apparatus has come to include a function of preventing a collision (see, for example, Patent Document 1).
To stop an actual machine before a collision, a check of the presence of a collision needs to be performed prior to an actual machine operation. For this purpose, an NC apparatus is configured to delay an instruction output to a machine by a time necessary to decelerate to a position where a collision is detected (see, for example, Patent Document 2).
Another NC apparatus is configured to calculate a virtual movement position in the next axis control cycle, calculate a distance necessary until when an operation stops by deceleration from an axis moving speed at this time, and perform a proximity check between parts of a machine at the distance (see, for example, Patent Document 3).
Normally, in an NC apparatus, a programmable logic controller (hereinafter, “PLC”) or a function equivalent thereto processes a command concerning an instrument other than an NC control axis, such as a tool replacement, turning of a turret tool post, and taking in and out of a tailstock instructed by an M.T instruction from a machining program, for example, (hereinafter, position-controlled instrument other than an NC control axis is referred to as “auxiliary machine”). The PLC also processes a state of an instrument such as a door lock sensor and a machine control panel.
A state quantity of an instrument including each auxiliary machine and sensor is allocated to a signal to a device of the PLC. For example, when an operation is completed, a signal of a certain device becomes ON, and the NC apparatus proceeds to the next process based on this. In this manner, the instrument takes a handshake with the device (hereinafter, “instrumental device”).
Patent Document 1: Japanese Patent Application Laid-open No. 2004-227047
Patent Document 2: Japanese Patent Application Laid-open No. 2007-172068
Patent Document 3: Japanese Patent Application Laid-open No. 2006-195862